The Islamic State terrorist group claimed responsibility for an attack in which a van ran over pedestrians in Barcelona in Las Ramblas boulevard. At least 13 persons were killed and more than 100 injured.
Confirming the death toll, Head of Catalonia's Regional Interior Department Joaquim Forn said in a tweet on Thursday: "My strongest condemnation of the terrorist attack in Barcelona. We can confirm 13 deaths."
He added that 15 of the injured were in serious condition and that the death toll was likely to rise, Efe news reported.
Claiming the attack, jihadi-affiliated news agency Amaq said the attackers were "soldiers of Islamic State".
The Mossos d'Esquadra regional police force said two persons have been detained in connection with the attack, though neither of them was the driver of the van.
A third person was found dead in his car 3 km from a police checkpoint where he exchanged shots with officers.
One of the arrested is Driss el-Ouakbir, a man of northwestern African origin who is believed to have rented the van used in the attack.
He told police his identity papers have been stolen. Spanish media reported that his 18-year-old brother could have stolen the papers and could also be involved in the attack, Xinhua news agency reported.
Ouakabir, a legal permanent resident of Spain, spent a month in pre-trial detention in 2012 after being accused of sexual assault in the town of Figueres, sources said.
The attack happened at 5.00 p.m. (local time) when the van rammed into several vehicles before barrelling down the tree-lined central pedestrian-only area of Las Ramblas. Regional police and emergency services were deployed to the area, which is at the heart of the city's touristic centre and is visited by thousands every day.
Interior Minister Forn said the Festa Major de Gracia, an iconic Barcelona celebration that began on Tuesday and was slated to end next Monday, would be cancelled.
Metro and train stations in the area were closed to the public, while people in the area of the attack were asked to stay where they are until the police can indicate an exit route.
Mossos d'Esquadra said that the van attack was related to an explosion on Wednesday night in coastal town of Alcanar, where a man was killed when gas-bombs he was handling detonated inside an abandoned house.
The aim of Thursday's assault was "to kill the maximum number of people", Mossos said on Twitter.
Meanwhile, Spanish Prime Minister Mariano Rajoy announced a three days of national mourning saying "terrorists are defeated by unity".